I've been told conflicting things by 3 different shops and even the manufacture websites. Can anyone on here advise what oil i should be using in a 2010 1.3 EFI piaggio porter?

On a different note my van is a 4x4 and i wanted to check/ change the transmission oil in the gearbox, back axle and front diff. Has anyone got the spec on the oil for these, i know there is an electronic diff lock somewhere in the system either the center or front as when i flick the 4x4 switch on the dash the turning circle is appalling so i'm guessing front?

It is constant 4wd with electric over air centre diff lock, NEVER NEVER put it in 4wd on a solid surface or you WILL get axle wind up when turning

When a 4WD is travelling in a straight line all four wheels rotate at the same speed, but during cornering each wheel travels at a different speed due to the radius of the turn. All vehicles have a differential on the front and rear axles to allow the wheels on the same axle to rotate at a different speed. Constant 4WD’s have a central differential fitted to allow for different speeds between front and back wheels, but most part-time four wheel drives do not.

When a part-time 4WD (without a centre differential) is in 4WD an attempts to corner on tarmac, all wheels need to rotate at different speeds, but without a centre differential they cannot. This creates the phenomena called "axle windup" or "transmission windup". High strain is placed on the drive shafts and transmission, eventually causing one of two things to happen. Either one of the wheels slips or spins to overcome the stress or the drive-shaft/transmission breaks. This is why part time 4WD’s should never select 4WD on tarmac.

Constant 4WD’s have a central differential within the transmission to overcome this problem. However once in the dirt a constant four wheel drive can be bogged with only one wheel spinning. This is why they have a central differential lock that stops the action of the centre diff and makes it like a part-time four wheel drive in 4WD mode. The centre diff lock should never be used on tarmac or non-slip surfaces for the reasons mentioned above.

In reality, a 4WD is only a two wheel drive with one front and one back wheel driving when traction is lost. One wheel on each axle spins while the other receives no drive at all due to the action of the differential. The exception to this is where a limited slip or locking differential is fitted. A limited slip diff allows a limited amount of drive to be applied to the stationary wheel before the other wheel on the same axle spins. A locking diff allows no slip at all and both wheels on the same axle turn at the same speed, regardless of the amount of traction.

Sometimes you can have get difficulty in getting out of 4WD when back on roads ie tarmac where you don't need it - it seems that the 4WD is locked in , don't attempt to drive away with it still engaged otherwise it will go KAHBOOM - can be expensive and I mean expensive .

Simply reverse your vehicle back about 4 metres and then drive forward again and try and disengage 4WD again, it should then disengage, if it doesn't repeat it again